It is often times necessary and/or desirable to utilize a catheter positioned within the body of a user, or patient, to drain a fluid from the body. Such a catheter might be needed, for example, to drain a body cavity such as the chest, bladder, or peritoneum.
Although hemodialysis is now the major method of support of end-stage renal disease patients in the United States, peritoneal dialysis has recently been utilized to a greater extent. This is due, at least in part, to peritoneal dialysis being relatively simple, painless, and not causing severe intradialytic symptoms. In addition, patient toleration of this type of dialysis has been found to be good even in the presence of systemic diseases besides renal failure.
While peritoneal dialysis was found to have numerous advantages, problems still remain, however, that are peculiar to this type of dialysis, including a requirement for large volumes of sterile fluid, the occurrence of infection, and particularly subcutaneous infections (due at least in part to catheter migration), the length of time required for treatment, and/or impedence or blockage of the outflow from the catheter.
The development of the silicone peritoneal catheter has allowed chronic peritoneal dialysis to become feasible. One of the best of such silicone catheters included a long subcutaneous tract and a curved intra-peritoneal portion, but problems still remained, including the occurrence of infection which proved to be a severe limitation. With the later addition of dacron cuffs, which cuffs prompted tissue in-growth, the occurrence of infections was greatly decreased.
In addition, while this type of catheter proved to function well during inflow, outflow, which is almost always slower than inflow, was found to be often inadequate and complete outflow obstruction was found to sometimes occur. This so-called "one-way" catheter obstruction may be due to upward dislodgement of the catheter, wrapping of the catheter by omentum, or constipation. In addition, the tendency to outflow obstruction was also found to be worsened by high flow rates in the peritoneal catheter.
To minimize the problems of omental obstruction of catheter drain holes, various modification has heretofore been suggested, including "stand-off" devices to hold the bowels away from the catheter (such as through the use of a balloon near the intra-abdominal end of the catheter, through the use of thin silicone rubber sheets in a position perpendicular to the intra-abdominal portion of the catheter and/or through the use of a catheter with a disc having a large plurality of small holes over the entire surface).
Even with modifications heretofore proposed and/or devised, problems of slow outflow and/or of one-way obstruction of peritoneal catheters still remained and improvements still were needed to affect, for example, a minimization of omentum involvement of the catheter, prevention of bowel obstruction of the catheter, and/or decrease of fluid inlet velocity to the catheter.
With respect to prior art patents, U.S. Pat. Nos. 3,818,511 and 3,707,967 show a catheter which can be implanted in a patient, while U.S. Pat. Nos. 4,160,454; 3,698,396; 3,520,298; and 3,064,653 relate to peritoneal catheters. In addition, the problem of catheter tip migration is discussed in U.S. Pat. No. 3,540,451.